A physical IaaS (Infrastructure as a Service) is a service that a service company rents physical servers which are installed in a data center to a user. The user accesses the physical server through an IP address (Internet Protocol address) which is assigned to the physical server, for example.
It is preferable to prepare the physical servers depending on the demand of the user in order to provide the service. However, because the users have a variety of demands, it causes to lose customers when system, which is met the demand of the user, is not provided. Therefore, it is preferable for the service company to have the physical servers from a high-performance physical server to a low cost physical server.
A technology of the physical IaaS provides physical servers by the pooling of hardware resources. The technology of the physical IaaS separates the hardware resources such as CPUs (Central Processing Unit), memories, and disk storage devices, etc. and pools the hardware resources. And the service company builds up the physical server by allocating (cutting and bringing) and assembling a hardware resource depending on the demand of the user from the pooled hardware resources. According to the physical IaaS, it is possible to flexibly constitute the physical server depending on the constitution requirements set by the user.
While, the physical server, which provides to the user, may be replaced due to trouble and maintenance. When the physical server is replaced, the MAC (Media Access Control) address to physically and uniquely correspond to the physical server is changed. Because user program has a possibility to use the MAC address, when the MAC address (called as physical MAC address) is changed, influence may produce to the service provided by the user (for example, a service provider). Therefore, a virtual MAC address, which is dynamically assigned, is provided to the user in behalf of the physical MAC address. By starting the physical server based on the virtual MAC address, even if the physical server is changed, it is avoided that the influence occurs for the service provided by the user.
It is disclosed in following patent documents 1 and 2 that the physical server has a plurality of MAC addresses.
[patent document 1] Japanese Laid-open Patent publication No. 2007-89019.
[patent document 2] Japanese Laid-Open Patent Publication No. Hei 10-135993.